1. Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Institute, Marshfield, Wisconsin, USA
2. Immunization Safety Office, US Centers for Disease Control and Prevention, Atlanta, Georgia, USA
3. Institute for Health Research, Kaiser Permanente Colorado, Aurora, Colorado, USA
4. Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA
5. Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California, USA
6. Division of Research, and Kaiser Permanente Vaccine Study Center, Kaiser Permanente Northern California, Oakland, California, USA
7. Center for Health Research,Kaiser Permanente Northwest, Portland, Oregon, USA
8. Biostatistics Unit, Kaiser Permanente Washington Health Research Institute, Seattle, Washington, USA